Radiotherapy In Prostate Cancer Patients Research Articles

Evaluative study between calculated and measured DVHs for advance techniques of radiotherapy for Prostate Cancer Patients

Evaluative study between calculated and measured DVHs for advance techniques of radiotherapy for Prostate Cancer Patients

Drug Intensification in Future Postoperative Radiotherapy Practice in Biochemically-Relapsing Prostate Cancer Patients.

Although salvage prostate bed radiotherapy is highly effective in biochemically-relapsing prostate cancer patients following prostatectomy, relapses remain frequent and improvements are needed. Randomized phase 3 trials have shown the benefit of adding androgen-depriving therapy to irradiation, but not all patients benefit from this combination. Preclinical studies have shown that novel agents targeting the androgen receptor, DNA repair, PI3K/AKT/mTOR pathways, or the hypoxic microenvironment may help increase the response to prostate bed irradiation while minimizing potential side effects. This perspective review focuses on the most relevant molecules that may have an impact when combined with salvage radiotherapy, and underlines the strategies that need to be developed to increase the efficacy of salvage post-prostatectomy radiotherapy in prostate cancer patients.

Can Dosiomics Features Be Relevant Predictive Factors for Biochemical Recurrence After Radiotherapy in Prostate Cancer Patients?

<h3>Purpose/Objective(s)</h3> Radiotherapy is one of the main treatment strategies for localized prostate cancer. Although several patients receive external radiotherapy, the relationships between dosimetric factors related to the treatment planning and biochemical recurrence (BCR) remain unclear. The aims of the present study were to develop a prediction model for BCR by integrating dose-based radiomics (dosiomics) features and clinical variables in prostate cancer patients, and to clarify the relationships between the dosimetric factors and BCR. <h3>Materials/Methods</h3> A total of 489 patients with adenocarcinoma of the prostate who had been prescribed a dose of 78 Gy in 39 fractions with intensity modulated radiation therapy from 2007 to 2014 were retrospectively enrolled. A total of 2,475 dosiomic features were calculated from the 3D doses in prostate, clinical target volume (CTV), and planning target volume (PTV), and relevant 8 clinical variables for BCR were also considered. Feature selection was performed to eliminate redundant or not significant features. Multivariate cox proportional hazards regression model was trained on the training cohort of 342 patients using the selected features, and the predictive performance was validated on the validation cohort of 147 patients using the concordance index (C-index). Kaplan-Meir curves with log-rank analysis was used to assess the univariate discrimination of freedom from biochemical failure (FFBF) between high- and low-risk BCR groups. <h3>Results</h3> A total of 96 patients developed BCR with the median time of 55.2 months. Two dosiomic features (1 from CTV and 1 from PTV) and three clinical variables were selected as predictive factors. Of the five, CTV (HGLRE) (hazard ratio [HR]: 0.73; 95% confidence intervals [CI]: 0.57-0.93; <i>P</i> = 0.01), pretreatment prostate-specific antigen (HR: 1.27; 95% CI: 1.04–1.55; <i>P</i> = 0.02) and positive biopsy core rate (HR: 1.40; 95% CI: 1.07–1.82; <i>P</i> = 0.01), were significantly associated with BCR. The C-index of the model in the validation cohort was 0.67 (95% CI: 0.65–0.68). CTV_wavelet-HHH_glrlm_HGLRE could significantly distinguish the patients into high- and low-risk groups (8-year FFBF: 76.6% vs. 87.5%, <i>P</i> < 0.01). <h3>Conclusion</h3> The dosiomic feature extracted from CTV can be a relevant predictive factor for BCR after radiotherapy in prostate cancer patients and may be useful as new metric for evaluating the quality of a treatment plan, instead of conventional dose indices.

Effect of Hydrogel Rectal Spacer on Intrafraction Prostate Motion During Radiotherapy of Prostate Cancer Patients

<h3>Purpose/Objective(s)</h3> Insertion of hydrogel rectal spacer may potentially stabilize the prostate by reducing intrafraction prostate motion. The purpose of this study was to investigate the effect of hydrogel rectal spacer on intrafraction prostate motion. <h3>Materials/Methods</h3> A retrospective review was conducted of prostate cancer patients treated from September 2015 to November 2018 who underwent external beam radiation therapy (EBRT) with intrafraction motion management using implanted electromagnetic transponders. There were 87 patients (73%) who received conventional fractionation, 16 (13%) moderate hypofractionation, 10 (8%) stereotactic body radiation therapy (SBRT) and 7 (6%) EBRT plus brachytherapy. The threshold for gating was set at 4 mm for conventional fractionation, 3 mm for moderate hypofractionation, and 2 mm for SBRT. Maximum prostate motion was measured by displacement outside of the gating threshold during treatment per fraction. Independent samples t-test was performed to compare prostate motion with and without hydrogel rectal spacer. <h3>Results</h3> We identified 120 patients with a total of 4447 fractions eligible for analysis. 49 patients (41%) were treated with hydrogel spacer and 71 (59%) without hydrogel rectal spacer. Mean displacement of prostate outside of the gating threshold was 4.9 mm (range, 2.1 – 12.8) and 5.6 mm (4.1 – 14.6) anteriorly, 2.6 mm (1.1 – 7.6) and 19.4 mm (4.0 – 25.8) posteriorly, 4.7 mm (2.2 – 8.3) and 12.5 mm (4.0 – 20.8) superiorly, 3.1 mm (1.1 – 8.2) and 14.2 mm (3.7 – 22.7) inferiorly, 4.3 mm (3.0 -12.4) and 4.5 mm (4.2 -7.6) left and 3.1 mm (3.1 – 4.1) and 4.3 mm (4.1 – 11.6) right for patients treated with and without hydrogel rectal spacer, respectively. There was a significant reduction of mean displacement in the posterior (2.6 mm vs. 19.4 mm, <i>P</i> = 0.04) and inferior direction (3.1 mm vs. 14.2 mm, <i>P</i> = 0.04) in patients with hydrogel rectal spacer compared to those without hydrogel rectal spacer during "beam on time". <h3>Conclusion</h3> The use of hydrogel rectal spacer can mitigate intrafraction prostate motion in posterior and inferior directions, suggesting a potential dosimetric advantage with the use of hydrogel rectal spacer. However, longer follow-up may be needed to confirm whether this translates into significant clinical benefit outweighing potential risk.

Pattern of Recurrence After Stereotactic Radiotherapy in Prostate Cancer Patients With Nodal Pelvic Relapse. A Multi-Institutional Retrospective Analysis

AimsCurrently, when nodal pelvic oligorecurrent disease is detected, no standard treatment option is recommended. One possible salvage option is nodal stereotactic body radiotherapy (SBRT). Here we analysed recurrence patterns after nodal SBRT in patients affected by pelvic oligometastatic relapse after radical prostatectomy, and androgen deprivation therapy (ADT)-free survival in this population. Materials and methodsData on 93 patients consecutively treated in five different institutions for pelvic oligorecurrent disease were reviewed. Inclusion criteria were biochemical recurrence after radical prostatectomy and imaging showing three or fewer metachronous lymphoadenopathies under aortic bifurcation. Patients underwent SBRT on all sites of disease. Concomitant ADT was allowed. ResultsAfter a median follow-up of 20 months (interquartile range 11–41), 57 patients had post-SBRT radiological evidence of relapse, for a median disease-free survival (DFS) of 15 months (95% confidence interval 9–24). Concomitant ADT was administered in 20 patients (21.5%). Overall, eight (8.6%), 21 (22.6%) and 28 (30.1%) patients had prostate bed only, pelvic nodal or distant relapse, respectively. The median ADT-free survival was not reached. Concomitant ADT, International Society for Urologic Pathology pattern at diagnosis < or ≥3, time to relapse ≤ or >12 months, prostate-specific antigen at recurrence < or ≥1.10 ng/ml and prostate-specific membrane antigen staging were not significantly associated with DFS. After relapse, 42 patients (45.2%) received a second SBRT course. ConclusionNodal SBRT yielded encouraging DFS and ADT-free survival in this population. Only a minority of patients developed prostate bed recurrence, suggesting that local treatment may be safely avoided. A consistent percentage of patients could be managed with a second SBRT course.

OC-0479 Towards CBCT-guided online adaptive radiotherapy for prostate cancer patients

OC-0479 Towards CBCT-guided online adaptive radiotherapy for prostate cancer patients

The impact of image acquisition time on registration, delineation and image quality for magnetic resonance guided radiotherapy of prostate cancer patients.

Background and PurposeMagnetic resonance (MR) guided radiotherapy utilizes MR images for (online) plan adaptation and image guidance. The aim of this study was to investigate the impact of variation in MR acquisition time and scan resolution on image quality, interobserver variation in contouring and interobserver variation in registration.Materials and MethodsNine patients with prostate cancer were included. Four T2-weighted 3D turbo spin echo (T2w 3D TSE) sequences were acquired with different acquisition times and resolutions. Two radiologists assessed image quality, conspicuity of the capsule, peripheral zone and central gland architecture and motion artefacts on a 5 point scale. Images were delineated by two radiation oncologists and interobserver variation was assessed by the 95% Hausdorff distance. Seven observers registered the MR images on the planning CT. Registrations were compared on systematic offset and interobserver variation.ResultsAcquisition times ranged between 1.3 and 6.3 min. Overall image quality and capsule definition were significantly worse for the MR sequence with an acquisition time of 1.3 min compared to the other sequences. Median 95% Hausdorff distance showed no significant differences in interobserver variation of contouring. Systematic offset and interobserver variation in registration were small (<1 mm) and of no clinical significance.ConclusionsOur results can be used to effectively shorten overall fraction time for online adaptive MR guided radiotherapy by optimising the imaging sequence used for registration. From the sequences studied, a sequence of 3.1 min with anisotropic voxels of 1.2 × 1.2 × 2.4 mm3 provided the shortest acquisition time without compromising image quality.

Prognostic comparison between radical prostatectomy and radiotherapy in prostate cancer patients at different stages and ages.

Radical prostatectomy (RP) and radiotherapy (RT) are both evidence-based nonconservative treatments for prostate cancer (PCa). However, which treatment is better remains controversial. This study aimed to compare the prognostic difference between radical prostatectomy (RP) and radiotherapy (RT) in PCa patients at different stages and ages. Two independent PCa cohorts (the Surveillance, Epidemiology, and End Results, SEER; and the Prostate, Lung, Colorectal, and Ovarian, PLCO) were employed. Cox regression was used to calculate the hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs). In both cohorts, patients who received RT exhibited a worse prognostic outcome than those who underwent RP. When stratified analysis was performed by tumor node metastasis (TNM) stage and age at diagnosis in the SEER cohort, the HR of RT versus RP for overall survival increased with TNM stage but decreased with age. Specifically, PCa patients in stage I in the age range of 55–84 years, stage IIA at 70–85+ years, and stage IIB at 75–85+ years had better survival with RT than RP patients (p < 0.05). In contrast, patients in stages IIA, IIB, III and IV with respective age ranges of 55–64 years; 50–74 years; 55–59, 65–74 years; and 45–74 years showed worse survival with RT compared with RP (p < 0.05). These findings were partially validated in the PLCO dataset. Our results indicated that the choice between RT and RP should be guided by TNM stage and age. These findings may facilitate counseling regarding the prognostic effect of RT and RP for PCa patients.

Deep learning-based synthetic CT generation for MR-only radiotherapy of prostate cancer patients with 0.35T MRI linear accelerator.

PurposeTo develop a deep learning model to generate synthetic CT for MR‐only radiotherapy of prostate cancer patients treated with 0.35 T MRI linear accelerator.Materials and MethodsA U‐NET convolutional neural network was developed to translate 0.35 T TRUFI MRI into electron density map using a novel cost function equalizing the contribution of various tissue types including fat, muscle, bone, and background air in training. The impact of training time, dataset size, image standardization, and data augmentation approaches was also quantified. Mean absolute error (MAE) between synthetic and planning CTs was calculated to measure the goodness of the model.ResultsWith 20 patients in training, our U‐NET model has the potential to generate synthetic CT with a MAE of about 29.68 ± 4.41, 16.34 ± 2.67, 23.36 ± 2.85, and 105.90 ± 22.80 HU over the entire body, fat, muscle, and bone tissues, respectively. As expected, we found that the number of patients used for training and MAE are nonlinearly correlated. Data augmentation and our proposed loss function were effective to improve MAE by ~9% and ~18% in bony voxels, respectively. Increasing the training time and image standardization did not improve the accuracy of the model.ConclusionA U‐NET model has been developed and tested numerically to generate synthetic CT from 0.35T TRUFI MRI for MR‐only radiotherapy of prostate cancer patients. Dosimetric evaluation using a large and independent dataset warrants the validity of the proposed model and the actual number of patients needed for the safe usage of the model in routine clinical workflow.

Secondary cancer risk from modern external-beam radiotherapy of prostate cancer patients: Impact of fractionation and dose distribution.

Modern radiotherapy (RT) uses altered fractionation, long beam-on time and image-guided procedure. This study aimed to compare secondary cancer risk (SCR) associated with primary field, scatter/leakage radiations and image-guided procedure in prostate treatment using intensity-modulated RT (IMRT), CyberKnife stereotactic body RT (CK-SBRT) in relative to 3-dimensional conformal RT (3D-CRT). Prostate plans were generated for 3D-CRT, IMRT (39 fractions of 2 Gy), and CK-SBRT (five fractions of 7.25 Gy). Excess absolute risk (EAR) was calculated for organs in the primary field using Schneider’s mechanistic model and concept of organ equivalent dose (OED) to account for dose inhomogeneity. Doses from image-guided procedure and scatter/leakage radiations were determined by phantom measurements. The results showed that hypofractionation relative to conventional fractionation yielded lower SCR for organs in primary field (p ≤ 0.0001). SCR was further modulated by dose-volume distribution. For organs near the field edge, like the rectum and pelvic bone, CK-SBRT plan rendered better risk profiles than IMRT and 3D-CRT because of the absence of volume peak in high dose region (relative risk [RR]: 0.65, 0.22, respectively, p ≤ 0.0004). CK-SBRT and IMRT generated more scatter/leakage and imaging doses than 3D-CRT (p ≤ 0.0002). But primary field was the major contributor to SCR. EAR estimates (risk contributions, primary field: scatter/leakage radiations: imaging procedure) were 7.1 excess cases per 104 person–year (PY; 3.64:2.25:1) for CK-SBRT, 9.93 (7.32:2.33:1) for IMRT and 8.24 (15.99:2.35:1) for 3D-CRT (p ≤ 0.0002). We conclude that modern RT added more but small SCR from scatter/leakage and imaging doses. The primary field is a major contributor of risk which can be mitigated by the use of hypofractionation.

Adjuvant versus early salvage radiotherapy for prostate cancer patients: Time to move on

In the management of prostate cancer , few treatments have caused as much controversy as adjuvant radiotherapy (ART) after radical prostatectomy in high-risk patients In the present article, we assess the exclusion and inclusion criteria of the 6 randomised trials and 5-year biochemical relapse-free survival and overall survival rates in order to identify the patient subgroups most likely to benefit from ART. We also evaluate treatment-related toxicity and the indications for androgen deprivation therapy . The main aim of this analysis was to determine whether the available evidence, which previously appeared to support ART, now favours early salvage radiotherapy. If so, perhaps we can finally resolve the controversy surrounding the optimal timing of postoperative radiotherapy

Short-Term Haematogical Effects of Androgen Deprivation and Radiotherapy in Prostate Cancer Patients

Androgen deprivation therapy (ADT) is known to cause a decline in hemoglobin (Hgb), but the effect on other blood parameters is less well studied. In the lab, androgen manipulation has an effect on leukocyte counts. We evaluated the effects of androgen ablation alone on Hgb, white blood cell (WBC), granulocyte, and lymphocyte counts in 99 prostate cancer patients. In addition, since radiation therapy decreases those counts, we evaluated whether the addition of ADT makes it worse, comparing 162 patients receiving both radiation and ADT to 149 patients with radiation alone. ADT alone did significantly (but minimally) cause a drop in the Hgb (~0.5 g/dl), the WBC (-0.39 × 103/μl) and granulocyte (-0.32 × 103/μl), but not the lymphocyte counts. The combination of ADT with radiation did cause a greater decline in the Hgb levels at the end of treatment, but at follow up there was no difference. There was no additional effect on WBC, granulocytes or lymphocyte counts. Our results confirm clinically that ADT alone has minimal effect on WBC and its components and that there is no synergistic detriment of androgen ablation on the effects of radiation therapy on those cells.

Evaluative study between calculated and measured DVHs for advance techniques of radiotherapy for Prostate Cancer Patients

Evaluative study between calculated and measured DVHs for advance techniques of radiotherapy for Prostate Cancer Patients

Survival Outcomes of Radical Prostatectomy + Extended Pelvic Lymph Node Dissection and Radiotherapy in Prostate Cancer Patients With a Risk of Lymph Node Invasion Over 5%: A Population-Based Analysis

PurposeWe aimed to compare the efficacy of radical prostatectomy (RP) + extended pelvic lymph node dissection (ePLND) and radiotherapy (RT) in localized prostate cancer (PCa) patients with a risk of lymph node invasion (LNI) over 5%.MethodsThe Surveillance, Epidemiology, and End Results (SEER) databases were used to identify patients with PCa from 2010 to 2014. Propensity score matching (PSM) was performed to balance baseline characteristics between patients in different treatment groups. Kaplan-Meier curves and Cox regression were used to assess the effects of treatments on cancer-specific survival (CSS) and overall survival (OS).ResultsOverall 20584 patients were included in this study, with 4,057 and 16,527 patients receiving RP + ePLND and RT, respectively. After PSM, patients with RP + ePLND had similar CSS (5-year CSS rate: 97.8% vs. 97.2%, P=0.310) but longer OS (5-year OS rate: 96.0% vs. 90.8%, P<0.001) compared to those receiving RT. When separating RT cohort into external beam radiotherapy (EBRT) group and EBRT+ brachytherapy (BT) group, treatments with RP + ePLND and EBRT+ BT achieved equivalent OS and were both superior to EBRT alone (5-year OS rate: 96.0% vs. 94.4% vs. 90.0%, P<0.001). Subgroup analyses and multivariate analyses further confirmed the superiority of RP + ePLND and EBRT+ BT.ConclusionRP + ePLND and EBRT + BT were associated with better survival outcomes compared to EBRT alone in PCa patients with a probability of LNI over 5%. However, no survival difference was observed between RP + ePLND and EBRT + BT.

PO-1382: Incidental testicular doses during volumetricmodulated ARC radiotherapy in prostate cancer patients

PO-1382: Incidental testicular doses during volumetricmodulated ARC radiotherapy in prostate cancer patients

Retrospective audit of inter-fraction motion for pelvic node radiotherapy in prostate cancer patients

IntroductionPelvic lymph nodes move independently to the prostate. When delivering radiotherapy to prostate and pelvic lymph nodes, daily inter- and intra-fraction anatomical changes need to be accounted for. Planning target volume (PTV) margins, grown from the pelvic lymph node clinical target volume need to be determined, to account for this variation in position. MethodsTwenty patients who had daily online image guided radiotherapy to prostate and pelvic lymph nodes between April and December 2018 were selected. Ten pre-treatment verification images using cone beam CT from each patient were registered to pelvic bone anatomy, prostate soft tissue or fiducial markers and pelvic lymph node soft tissue to assess the accuracy of treatment delivery. Population systematic and random errors and PTV margins were calculated. ResultsPTV margins of 0.4 cm, 0.4 cm and 0.7 cm left–right (LR), superior–inferior (SI) and anterior–posterior (AP) respectively were derived for the pelvic lymph nodes when registering to prostate. PTV margins of 0.3 cm, 0.2 cm and 0.4 cm LR, SI and AP respectively were derived for the pelvic lymph nodes when registering to bone. There was a posterior systematic shift of the prostate during the treatment course. ConclusionThere is differential motion of pelvic lymph nodes to prostate and in the era of prostate and pelvic radiotherapy for patients with node positive prostate cancer; there is increasing importance in the accuracy of dose delivery to the involved lymph node. Hence, this group of patients may benefit from personalised radiotherapy PTV margins, especially if the involved pelvic lymph node is within the anterior part of the clinical target volume. Implications for practiceOptimisation of dose delivery to the pelvic lymph nodes when prioritising the prostate in prostate and pelvic lymph node image guided radiotherapy.

From fatigued to fit: an investigation of the impact of physical exercise in the management of radiotherapy-induced fatigue in prostate cancer patients

AbstractAim:The aim of this paper is to investigate the effectiveness of physical exercise in managing fatigue during radiotherapy for prostate cancer patients. It explores the impact of various physical exercise regimes and their role in the prevention and management of fatigue to help inform best practice.Method:A literature search was conducted on OVID Medline database with a follow-up search on google scholar to include relevant references found during the initial search. Relevant systematic reviews and randomised controlled trials (RCTs) arising from this search were reviewed.Findings:There is evidence to support the notion that physical exercise in all its forms is an effective and safe intervention for fatigue management for prostate cancer patients undergoing radiotherapy. Although widely studied, there is limited evidence of fatigue management strategies being clearly implemented into current radiotherapy practice for patients with prostate cancer. This information is essential to enable therapeutic radiographers to educate prostate cancer patients regarding effective exercise strategies and ensure that fatigue is managed optimally.Conclusion:Further research is required into the optimum physical exercise prescription to reduce radiation-induced fatigue, and standardised best practice guidelines should be developed nationally. A future move toward patient education into physical exercise and wellbeing should be a central component of the therapeutic radiographer role with specialist advice offered by review radiographers, empowering patients to become more physically active during treatment. Therapeutic radiographers have a unique opportunity to educate and promote physical exercise through a holistic wellbeing approach that aims to mitigate fatigue and improve quality of life.

High-dose-rate brachytherapy and hypofractionated external beam radiotherapy combined with long-term androgen deprivation therapy for very high-risk prostate cancer.

To estimate the outcomes of high-dose-rate brachytherapy combined with hypofractionated external beam radiotherapy in prostate cancer patients classified as very high risk by the National Comprehensive Cancer Network. Between June 2009 and September 2015, 66 patients meeting the criteria for very high-risk disease received high-dose-rate brachytherapy (2 fractions of 9Gy) as a boost of external beam radiotherapy (13 fractions of 3Gy). Androgen deprivation therapy was administered for approximately 3years. Biochemical failure was assessed using the Phoenix definition. The median follow-up period was 53months from the completion of radiotherapy. The 5-year biochemical failure-free, distant metastasis-free, prostate cancer-specific and overall survival rates were 88.7, 89.2, 98.5 and 97.0%, respectively. The independent contribution of each component of the very high-risk criteria was assessed in multivariable models. Primary Gleason pattern5 was associated with increased risks of biochemical failure (P=0.017) and distant metastasis (P=0.049), whereas clinical stage ≥T3b or >4 biopsy cores with Gleason score8-10 had no significant impact on the two outcomes. Grade3 genitourinary toxicities were observed in two (3.0%) patients, whereas no grade ≥3 gastrointestinal toxicities occurred. The present study shows that this multimodal approach provides potentially excellent cancer control and acceptable associated morbidity for very high-risk disease. Patients with primary Gleason pattern5 are at a higher risk of poor outcomes, indicating the need for more aggressive approaches in these cases.

Overexpression of IGFBP5 Enhances Radiosensitivity Through PI3K-AKT Pathway in Prostate Cancer.

BackgroundRadiotherapy is the main treatment for localized prostate cancer. The therapeutic effects of radiotherapy are highly dependent on radiosensitivity of target tumors. Here, we investigated the impact of insulin-like growth factor-binding protein 5 (IGFBP5) on irradiation therapy in prostate cancer.MethodsIGFBP5 gene was overexpressed in human prostate cancer cell lines, PC3 and DU145, with transfection of lentivirus expression vector. Radiosensitivity of the cell lines was assessed with colony formation, cell cycle and cell proliferation assays. The expression of proteins associated with the PI3K-AKT pathway was determined by Western blotting. The effect of IGFBP5 knockdown on PI3K-AKT pathway was tested using PI3K inhibitor.ResultsHigher expression of IGFBP5 improved the efficacy of radiotherapy for prostate cancer patients. The effects of IGFBP5 were linked to the PI3K-AKT signaling pathway. Overexpression of IGFBP5 enhanced radiosensitivity and induced G2/M phase arrest in prostate cancer cells. In contrast, it decreased PI3K, p-AKT expression and cell viability. These effects were reversed by IGFBP5 knockdown.ConclusionOur results reveal that IGFBP5 regulates radiosensitivity in prostate cancer via the PI3K-AKT pathway. It is, therefore, a potential biomarker of tumors that influences the therapeutic effect of radiotherapy.

18F-choline PET/CT driven salvage radiotherapy in prostate cancer patients: up-date analysis with 5-year median follow-up.

Salvage radiotherapy is generally considered as the standard treatment for biochemical relapse after surgery. Best results have been obtained with a PSA value < 0.5ng/ml at relapse, while 60-66Gy is deemed as standard total dose. Modern imaging, as dynamic-18F-choline PET/CT may identify site of recurrence, allowing dose escalation to a biological target volume. Hundred and fifty patients showed a local relapse at dynamic-18F-choline PET/CT at time of biochemical recurrence. High-dose salvage radiotherapy was delivered up to total dose of 80Gy to 18F-choline PET/CT positive area. Toxicity and relapse-free survival were recorded. Median PSA value at the beginning of salvage radiotherapy was 0.47ng/ml (range 0.2-17.5ng/ml). One-hundred and thirty nine patients (93%) completed salvage radiotherapy without interruptions. Acute gastrointestinal grade ≥ 2 toxicity was recorded in 13 patients (9%), acute genitourinary grade ≥ 2 toxicity in 2 patients (1.4%). One patient (0.7%) experienced late gastrointestinal grade 4 toxicity and 2 patients (1.4%) late acute genitourinary grade 3 toxicity. With a median follow-up of 63.5months, 5 and 7-years relapse-free survival were 70% and 60.7%, respectively. With a median follow-up of 5years the present study confirms that high-dose salvage radiotherapy to a biological target volume is feasible, with low rate of late toxicity and promising activity.